Multi-passage muffler insert for exhaust pipe



July 26, 1966 o. F. BORGESON 3,262,516

MULTI-PASSAGE MUFFLER INSERT FOR EXHAUST PIPE Filed March 9, 1964 INVENTOR.

4 6m. mm

AGENT United States Patent 3,262,516 MULTI-PASSAGE MUFFLER INSERT FOR EXHAUST PIPE Otto F. Borgeson, 604 Pasqual Ave., San Gabriel, Calif. Filed Mar. 9, 1964, Ser. No. 350,171 3 Claims. (Cl. 18144) The invention herein described pertains to mufflers for internal combustion engines, and more particularly to mufilers for internal combustion engines installed in boats.

Mufflers are conventionally installed somewhere between the exhaust ports of the engine and the exhaust pipe that releases the exhaust gases into the surrounding atmosphere. When such muifiers are replaced, it is consequently necessary to disconnect the exhaust pipe, interpose a new muffler in the exhaust system and then attach the exhaust pipe to the new mufller. One of the objects of the present invention is to simplify such replacements as well as the' original installations of mufilers by providing a muffling device that may be mounted within the exhaust pipe itself. This is particularly feasible in boats where the exhaust pipes are frequently three or four inches in diameter.

Another object is to provide a mufiler of the type described that may be positioned coaxially within the exhaust pipe by means of mounting members of such design that individual adjustments may be made to permit a relatively few sizes of muffiers to be adapted to a wide range of exhaust pipe sizes.

An additional object is to provide an efiicient mufiler for motor boats that will be inexpensive to build.

Still another object is to provide a design for mufflers of the type described that will make itpossible to construct the mufflers entirely from stampings, thus materially reducing their cost.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of an embodiment of the invention. For this purpose, such an embodiment is shown in the drawings accompanying and forming a part of the present specification. This embodiment will now be described in detail, illustrating the general principles of the invention; but it is to be understood that this detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims. p

In the drawings:

FIGURE 1 is a longitudinal section through a portion of an exhaust pipe with the muffler coaxially mounted therein, the section extending through the mufiler itself;

FIG. 2 is a cross-section taken substantially on the line 22 of FIG. 1;

FIG. 3 is a section taken on line 33 of FIG. 1;

FIG. 4 is a section taken on line 44 of FIG. 1; and

FIG. 5 is a cut-away view of a portion of the muffler showing one of the vents that is formed in its surface.

In the presently preferred embodiment of the invention, the body or shell of the mufiler 44 is formed of two identical complementary parts 11 and 12, each having a pair of oppositely extending peripheral flanges 13 and 14 whereby the complementary halves of the shell are connected together in any suitable manner, as by rivets or spot welding. One end of the shell portion is provided -with a funnel, or bell-shaped, inlet 15 that may be formed in any appropriate way as by means of casting, spinning or stamping, but preferably the latter. The inlet 15 is mounted coaxially on one end of the shell in such a manner that little obstruction will be offered to the gases entering the funnel-like inlet and proceeding into the shell proper.

The end of the shell opposite from the inlet 15 is pro- "ice vided with a closure 16. This closure has a central aperture 17 therein through which,'in the presently preferred embodiment of the invention, a bolt 18 extends, the internal end of this bolt being suitably secured to a disc 19, the purpose of which will hereinafter become apparent.

The periphery of the shell has a plurality of louvers 20 formed therein. In the illustrated embodiment of the invention, there are two series or groups of individual .as shown at 22 so that gases entering the inlet 15 and bouncing back from the disc 17 or plate 19 will be directed by the ear-shaped portions 22 of the louvers toward a the convex outer surface of the inlet 15.

A plurality of lugs or fins 23 are spaced, preferably equally, around the periphery of the muflier. These may be individual parts appropriately secured to the shell, or they may be radial extensions of a ring 25 surrounding the shell, or of two complementary halves of such a ring. The fins 24 may be formed integrally with the small end 45 of the funnel-like gas inlet 15. This reduced portion 45 may be slipped or pressed over and around the end of the shell that is opposite from its closed end. The various lugs23 and 24 are provided with bent-over portions 27 to facilitate the insertion of the mufiier with its projecting fins and lugs into the exhaust pipe 26-from the right end toward the left end, the left end of the portion of the exhaust pipe 26 shown in FIG. 1 being the end that is closest to the engine. The fins or lugs 23 and 24 may be adjusted to adapt the muffler to different sized exhaust pipes by bending them outwardly until they en- 'gage'the inside of the walls of the exhaust pipe. The lugs 24 in FIG. 1 are shown bent out to such adjusted position. The lugs 23 in FIG. 1 are also in adjusted position but are disposed on radii that places their bent-over ends further back from the plane on which the longitudinal'section is taken. The bending of these fins or lugs is done as the muffler is inserted into the exhaust pipe at the time of installation.

A disc 28 having radially extending project-ions 29 is secured as by Welding to the closure member 16 of the end of the mutfier opposite from the inlet bell 15. The projections 29 are provided with beads 30 extending radially thereof in order to strengthen the projections. These projections are so formed on the central portion 28 of the disc that they form an obtuse angle with respect having an uninterrupted circular periphery, is provided with a central aperture 33 so that the disc may be slipped over the bolt 18 and received within the cupped region circumscribed by the projections 29 of the inner disc 28.

In the assembly of te mufiier, a nut 34 is threaded over the outer end of the bolt 18. This nut bears against the disc 3'1whose' periphery 32 may be tightened against the fingers =29 to spread them outwardly so that their relatively sharp outer ends 35 will dig into the inner wall of the exhaust pipe in order to hold the muffler tightly in position. The force of the gases against the concave walls 36 of the inlet bell and against the disc 19 adjacent the closure 16 urges the entire mufiier structure toward the right, thus causing the ends 35 of the fingers to bite into the inner walls of the exhaust pipe.

The beads or ribs 30 not only serve to strengthen and stiffen the fingers 29, but also supply a curved surface against which the periphery 32 of the disc 31 may bear and slide as the nut 34 is tightened firmly against the disc 31 for spreading the fingers.

It is not absolutely essential that the disc 28 be riveted or welded to the closure member 16, as the member 28 is quite securely held in place mechanically. Its central aperture 37 which surrounds bolt 18 positions the disc, and the firm pressure of the periphery 32 of the disc 31 against the fingers 29 clamps the entire end assembly together.

The exhaust gases move through the exhaust pipe from left to right when the parts are positioned as shown in FIG. 1. The greater portion of these gases enters the funnel-shaped inlet .15, and the remainder passes around it. When the gases that have entered the shell reach the disc 19 at the end of the chamber opposite from the inlet, they are deflected and escape out of the shell through the louvers 22 where they encounter the gases that have passed around the muffler and which are traveling from left to right through the exhaust tube. The gases that are escaping through the louvers 22 thus create tunbulence with the gases surrounding the shell; and turbulence, of course, breaks up sound Waves and mufiies the sound.

Turbulence is also created within the shell itself between the gases that are approaching the right end of the enclosure and those that are being deflected back therefrom toward the louvers. The turbulence in these various areas is indicated by the wavy or looped arrows in the regions where the turbulence takes place.

The radial projections 23 and 24 that extend out from the peripheral portions of the shell between the louvers and the bell-shaped inlet 15 are staggered as indicated in FIG. 2 so that the gases will encounter temporary obstructions all around .the shell. A portion of the gases that has passed between the lugs 24 in the forward ring strikes the lugs 23 in the next ring. This mechanical interference with the fast moving gases also produces helpful turbulence. Still additional turbulence is produced by the fingers 29 around the closed end of the shell.

The various holes 38 in the disc 31 that spreads the fingers 29 serve the double function of lightening the disc and causing another region of turbulence.

In motor boats, part of the water that cools the engine is released into the exhaust system for further cooling purposes. Some of this water flows under the bell-shaped inlet 15 and beneath the shell, and some of it enters the shell itself through the inlet. The fast moving gases force some of the water into the louvers on the lower side of the shell. The churning water and gases produce a most effective muflling effect.

Although the illustrated embodiment of the described invention is one that may be readily made from stampings, the invention may of course be embodied in similar structures that may be assembled from parts which may be cast or formed in any other appropriate manner. Many modifications may of course be made from the embodiment shown, and other elements may be substituted for those described; and these may be rearranged, reversed and repositioned-all without departing from the broad spirit of the invention as succinctly set forth in the appended claims.

The inventor claims:

!1. A muflier comprising: an elongated shell adapted to be positioned lengthwise within an exhaust pipe of an internal combustion engine, said shell flared outward at one end to form a funnel-like structure whose maximum diameter is greater than that of the main body of the shell but less than the internal diameter of said pipe; a plurality of louvers in the wall of said shell having their external diverging portions directed toward the exterior of said funnel-like structure; said shell closed at the end opposite from said structure; a plurality of first lugs carried by said shell and spaced therearound adjacent said opposite end; a plurality of second lugs carried by said shell and spaced therearound intermediate said louvers and said funnel-like structure; said first and second lugs acting to position said shell coaxially of said pipe; and said louvers acting to permit the gases received within said shell through said funnel-like structure to escape to the exterior of the shell against the gases moving through said pipe toward said first lugs from the region around said funnel-like structure, thereby creating turbulence in the gases around the shell to break up the sound Waves in said gases.

2. A mufiier comprising: an elongated shell adapted to be positioned lengthwise Within an exhaust pipe of an internal combustion engine, said shell closed at one end and flared outward at the other end to form a funnel-like gas inlet whose maximum diameter is greater than that of the main body of the shell but less than the internal diameter of said pipe; a plurality of first lugs carried by said shell and spaced therearound adjacent said other end; a plurality of second lugs carried by said shell and spaced therearound intermediate said first lugs and said funnel-like gas inlet, said first lugs angularly staggered with respect to said second lugs for intercepting portions of the exhaust gas stream that have passed between the second lugs; said first and second lugs engaging the inner Wall of said exhaust pipe and acting to position said shell coaxially of said pipe; a plurality of louvers in the wall of said shell for directing gas from within said shell outwardly thereof against the gases moving through said pipe in an opposite direction from the region around said funnel-like structure, thereby creating turbulence in the gases around the shell to break up sound waves.

3. A muffler comprising: an elongated shell adapted to be positioned lengthwise within an exhaust pipe of an internal combustion engine, said shell closed at one end and flared outward at the opposite end to form a funnellike gas inlet whose maximum diameter is greater than that of the main body of the shell but less than the internal diameter of said pipe; skeletal means for positioning said shell coaxially of said pipe, said means including (a) a plurality of lugs spaced around the closed end of the shell and so inclined at an obtuse angle with respect to the shells periphery that the fingers diverge from each other, (b) a threaded rod protruding from the center of the closed end, (c) a centrally apertured disc mounted on said rod, and (d) a nut threaded on said rod against the exterior surface of said disc for urging it toward said closed end and against said lugs for spreading them outwardly against the inner wall of the exhaust pipe; and a plurality of louvers in the wall of said shell for directing gas from within said shell outwardly thereof against the gases moving through said pipe in an opposite direction from the region around said funnel-liike structure, thereby creating turbulence in the gases around the shell.

References Cited by the Examiner UNITED STATES PATENTS 1,860,892 5/ 1932 Gray 181--45 2,035,923 3/1936 S'carritt 18144 3,036,65 3 5/ 1962 Calabresi 18144 3,104,732 9/1963 Ludlow et al. 18136 8,146,850 9/ 1964 Ludlow et al. 181--61 X FOREIGN PATENTS 842,962 3/ 1939 France.

28,686 3/ 1918 Norway.

RICHARD B. WILKINSON, Primary Examiner. LEO SMILOW, R. S. WARD, Assistant Examiners. 

1. A MUFFLER COMPRISING: AN ELONGATED SHELL ADAPTED TO BE POSITIONED LENGTHWISE WITHIN AND EXHAUST PIPE OF AN INTERNAL COMBUSTION ENGINE, SAID SHELL FLARED OUTWARD AT ONE END TO FORM A FUNNEL-LIKE STRUCTURE WHOSE MAXIMUM DIAMETER IS GREATER THAN THAT OF THE MAIN BODY OF THE SHELL BUT LESS THAN THE INTERNAL DIAMETER OF SAID PIPE; A PLURALITY OF LOUVERS IN THE WALL OF SAID SHELL HAVING THEIR EXTERNAL DIVERGING PORTIONS DIRECTED TOWARD THE EXTERIOR OF SAID FUNNEL-LIKE STRUCTURE; SAID SHELL CLOSED AT THE END OPPOSITE FROM SAID STRUCTURE; A PLURALITY OF FIRST LUGS CARRIED BY SAID SHELL AND SPACED THEREAROUND ADJACENT SAID OPPOSITE END; A PLURALITY OF SECOND LUGS CARRIED BY SAID SHELL AND SPACED THEREAROUND INTERMEDIATE SAID LOUVERS AND SAID FUNNEL-LIKE STRUCTURE; SAID FIRST AND SECOND LUGS ACTING TO POSITION SAID SHELL COAXIALLY OF SAID PIPE; AND SAID LOUVERS ACTING TO PERMIT THE GASES RECEIVED WITHIN SAID SHELL THROUGH SAID FUNNEL-LIKE STRUCTURE TO ESCAPE TO THE EXTERIOR OF THE SHELL AGAINST THE GASES MOVING THROUGH SAID PIPE TOWARD SAID FIRST LUGS FROM THE REGION AROUND SAID FUNNEL-LIKE STRUCTURE, THEREBY CREATING TURBULENCE IN THE GASES AROUND THE SHELL TO BREAK UP THE SOUND WAVES IN SAID GASES. 